High-voltage circuit-breaker



Jan. .16, 1962 A. c. KLAASSEN HIGH-VOLTAGE CIRCUIT-BREAKER 2 Sheets-Sheet 1 Filed Aug. 20, v1959 I INVENTOR- BY 4/25". K04 ZMAZ ya/wa HWOKMf/S Jan. 1-6, 1962 A. CQKLAASSEN HIGH-VOLTAGE CIRCUIT-BREAKER 2 Sheets-Sheet 2 Filed Aug. 20, 1959 INVENTOR. 11M wbm ,fi d/Mw,

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The invention relates to a high-voltage circuit-breaker for a limited cirouit-breaking capacity, having as movable contact at least one contact pin, which in the closed condition of the circuit-breaker lies in a contact chamber of insulating material in which the stationary contact is accommodated, a conductive sleeve being associated with 'the contact pin, which in the closed condition of the circuit-breaker surrounds the outside of the contact chamber, engages the stationary contact, and is coupled with the contact pin so as to be relatively movable in such a way that when the circuit-breaker is opened, the conductive sleeve is disengaged from the stationary contact prior to the contact pin. A circuit-breaker of such a kind is known from the British patent specification No. 480,377, FIGURE 1 and the US. patent specification No. 2,455,998, FIGURE 3.

The advantages to be named hereinafter are not mentioned in these references, nor do they contain any indication in this direction. The advantage of the said conductive sleeve is that when the circuit-breaker is closed, there will be no electric field in the space between the contact pin and the material of the contact chamber, owing to which in the said space ionization is also prevented, which has the favourable consequence that corrosion of the contact pin and the material of the contact chamber is avoided.

Another advantage of the conductive sleeve is that the latter serves as a current path connected in parallel with the contact pin, wherein the current which can be permanently carried through the circuit-breaker becomes of. approximately the same magnitude as the maximum current that can be switched by the contact pin (in particular: switched in, because the striking discovery has been made that the maximum current-closing intensity can be appreciably higher than the maximum current-interrupting intensity).

In the known circuit-breaker, however, the arrangement-as stated-is such that when the circuit-breaker is closed, the contact pin engages the stationary contact prior to the conductive sleeve. This entails the disadvantage that upon the occurrence of pre-ignition, i.e. of an arc, prior to the moment when upon the closing of the circuit-breaker the contact pin engages the stationary contact, the contact pin may recoil owing to the rapidly in creasing pressure in the contact chamber, while further owing to the high mechanical load on the wall of the contact chamber said chamber is in danger of exploding.

According to the invention these disadvantages ar obviated by the circumstance that the movability of the conductive sleeve relative to the contact pin is such that when the circuit-breaker is closed, the conductive sleeve engages the stationary contact prior to the contact pin.

Owing to this measure pre-ignition can no longer occur between the contact pin and the stationary contact, because previously the contact pin has entered into electric connection with the stationary contact via the conductive sleeve.

In principle it is indeed possible for pregnition to occur between the conductive sleeve and the stationary contact, but the chances of this are much smaller than those of pre-ignition in the contact chamber, because in the contact chamber the fouling is greater than outside. Moreover the Patent ice pressure can never rise to such high values outside the con tact chamber as it can inside.

The features of this invention promote the smooth closing of the circuit-breaker under any circumstances.

The invention will be elucidated with reference to an embodiment which is shown in the drawing. Each of the three figures it comprises shows only one half of the circuit-breaker, as far as its centre-line.

FIGURE 1 shows the circuit-breaker at the beginning of the closing movement, FIGURE 2 in closed condition, and FIGURE 3 during the opening movement.

The circuit-breaker consists of a stationary part lying at the bottom and a movable part lying at the top. These will be discussed in succession.

The stationary part comprises two stationary contacts 1. Each of these consists of a central portion 3 and an outer portion 4. Between these two portions a cylindrical insulating contact chamber 5 is present. The two stationary contacts 1 and the two contact chambers 5 are jointly surrounded by a sheath 6 which, like the part in which the stationary contacts 1 are accommodated, is made of an electrically high-grade insulating material, e.g. casting resin. Lying between the two stationary contacts 1 and the two contact chambers 5, and incorporated likewise in the insulating material, is a permanent magnet system consisting of two paramagnetic pole plates 7, separated by a number of permanent magnets 9 polarized in the same direction. At the top the pole plates 7 extend slightly beyond the adjacent insulating material. Owing to this, a paramagnetic aramature plate 13 to be discussed presently can be brought directly into contact with the pole plates 7 and 8.

The movable part of the circuit-breaker consists of a hood 10 of insulating material, eg. casting resin, with a handle 11. The dimensions of the hood are such that it can be pushed with a free fit on the sheath 6 of the stationary part.

In the hood 10, two electrically interconnected metal sleeves 12 are fitted at a distance from each other equal to that between the stationary contacts 1. Each metal sleeve 12 is provided on the side turned towards the centre-line of the circuit-breaker with a fairly wide axial notch over about one half of its length, reckoned from the handle 11. Extending between the twosleeves 12 and at right-angles thereto is an armature plate 13 of paramagnetic material. This can be displaced in the longitudinal direction of the sleeves 12 relative to said sleeves, and thus moves through the axial notches in said sleeves. Near its free end each of the sleeves 12 is provided on the inside with a flange 8. Between the flange 8 and the armature plate 13 in each sleeve 12 there is a helical spring 14, which serves as circuit-breaking spring in a way to be described presently. By the circuitbreaking springs 14 each of the ends of the armature plate 13 is forced in the direction of the handle 11. The armature plate 13 is supported against a forked internal projection 15 of the hood 10.

The armature plate 13 supports a U-shaped movable switching member 16, each of whose ends is formed by one of the movable contact pins 17. The U-shaped switching member 16 can be displaced relative to the armature plate 13 in the direction of the handle 11. In FIGURE 1 the central part of the switching member 16 is held resiliently against the armature plate; in fact, around each of the legs of the switching member 16, i.e. on each of the contact pins 17, is fitted a helical spring 18, which at one end rests under pressure against the armature plate 13 and at the other end against an external flange 19 of the respective contact pin 17.

In the opened condition of the circuit-breaker the-components of the movable part of it are positioned relative to each other as shown in FIGURE 1. In that case, however, the whole of the movable part has been lifted from the stationary part. The stationary contacts 1 and the contact chambers are then sheltered in the space surrounded by the sheath 6.

When the circuit-breaker is to be closed, the hood 11) is pushed on the sheath 6. In this movement after a certain time the free end of each of the metal sleeves 12 engages the outer portion 4 of the corresponding stationary contact 1. In this way the circuit between the two stationary contacts 1 is closed. This stage is illustrated in FIGURE 1.. The free end of each of the contact pins 17 does not yet engage the central portion 3 of the corresponding stationary contact 1. Thus, recoil of the contact pin 17 owing to pro-ignition is prevented in the way described. A pre-ignition of this type is no longer possible. Any pro-ignition that may occur between the metal sleeve 12 and the outer portion 4 of the stationary contact 1 takes place outside the contact chamber 5 and thus may only lead to a very much lower pressure.

If the hood is pushed over the sheath 6 beyond the position of FIGURE 1, after some time the free end of each contact pin 17 engages the corresponding central portion 3 of the stationary contact 1. At this moment pre-ignition is no longer possible, because each of the sleeves 12 already engages the corresponding stationary contact 1, so that the circuit over the circuit-breaker is closed.

After the contact pin 17 has engaged the stationary contact, upon further movement of the hood 10 the helical spring 18 is compressed. The pin 17 is therefore forced against the stationary contact 1 by the compression of this spring. The spring 18 acts as a contact pressure spring. The hood 10 can be pushed on the sheath 6 until the armature plate 13 comes into contact with the pole plates 7. The circuit-breaker is then in the closed condition. It remains in this condition because the armature plate 13 is held by the pole plates 7 under the influence of the permanent magnets 9. This position is illustrated in FIGURE 2. Between the armature plate 13 and the central part of the switching member 16 there is now a space the height of which is equal to the length of compression of the contact pressure springs 18.

FIGURE 3 serves to illustrate the opening of the circuit-breaker.

The opening is elfected by pulling the handle 11. The hood 10 then moves backward and each of the metal sleeves 12 is taken along, so that it is disengaged from the outer portion 4 of the respective stationary contact. The armature plate 13, however, is held by the pole plates 7. In consequence, the circuit-breaking spring 14- is compressed. The compression of this circuit-breaking spring 14 continues to increase until, as shown at A, the (non-notched) part of the metal sleeve 12 comes into contact with the armature plate 13. The pull exerted on the handle 11 is then transmitted direct by the sleeve 12'to the armature plate 13. The result is that the armature plate 13 is pulled off the pole plates 7. As soon as it has moved away an extremely short distance from said pole plates, the force exerted by the pole plates 7 falls practically to zero. The consequence is that each of the now compressed circuit-breaking springs 14 accelerates the armature plate 13 upwardly. After a short time the armature plate 13 comes into contact with the central part of the U-shaped switching member 16, as a result of which the end of each of the contact pins 17 is pulled off the correspondin stationary contact 1 with a erk. In this way a good interruption of the circuit in each of the contact chambers 5 is always ensured.

The movement of the armature plate 13 under the influence of each of the circuit-breaking springs 14 continues until the armature plate 13 has come into contact again with the internal projection of the hood 1! Any are that may have occurred in each of the contact chambers 5 has then already been extinguished. When the hood 10 has been completely taken from the sheath :6, it may be put aside, along with all the parts present in it,

4 which are then in the relative position of FIGURE 1 a am.

From the operation described it appears that during both the closing and the opening of the circuit-breaker the action of each of the metal sleeves 12 precedes that of the corresponding contact pin 17.

The invention is not restricted to the embodiment shown in the drawing.

Thus it is not necessary for the two contact pins 17 to be integral with the central part of the Ushaped switching member 16. These pins may also be connected with each other by an altogether difierently constructed conductor, e.g. a fuse.

Nor is it necessary for the movable switching member to be U-shaped and to serve for double interruption and closing respectively of the circuit. In the case of single interruption the invention can in principle be applied equally well.

What I claim is:

l. A high voltage circuit breaker comprising stationary contact means having an inner portion and an outer portion with :an insulating member separating the ends of said portions, insulating means movably mounted relative to said contact means, a conducting sleeve mounted on said insulating means in a position to engage said outer portion of said stationary contact, a switching member slidably mounted relative to said sleeve in a position: to engage said inner portion of said stationary contact, and means innerconnecting said sleeve and said switch-' ing member whereby said conducting sleeve makes con-- tact with said outer portion before said switching member makes contact with said inner portion during theclosing of said switch and wherein said switching member disengages said inner portion after said sleeve disengages said outer portion during the opening of said switch.

2. A circuit breaker according to claim 1, further including a plate member slidably mounted relative to said sleeve and wherein said means connected to said switching member comprises spring means and connecting means on said sleeve, said spring means being compressed between said plate member and said connecting means.

3. A circuit breaker according to claim 2, further comprising second spring means, connecting means on said c switching member, said second spring means being compressed between said plate member and said last-mentioned connecting means, magnet means positioned to apply a holding force to said plate member when said switch is in a closed position until said holding force is exceeded by the force of said first-mentioned spring means, wherein upon movement of said sleeve away from said stationary contact, said switching member disengages said inner portion only after said sleeve disengages said outer portion.

4. A high voltage switch comprising an insulating support, a contact mounted on said support and having inner and outer portions projecting therefrom and separated by an insulating member, insulating means movably mounted relative to said support, a conducting sleeve secured to said insulating means and positioned to engage said outer portion, a switching member having a portion slidably mounted within said sleeve, a plate member having a portion slidably mounted relative to said sleeve and positioned to engage a portion of said sleeve, connecting means on the inner surface of said sleeve, first spring means compressed between said connecting means and said plate member and urging said plate member in a first axial direction relative to said sleeve, and second spring means connected to said switching member and compressed between said switching member and said plate member, urging said switching member in the opposite axial direction to that of said plate member, whereby said conducting sleeve makes contact with said outer portion before said switching member makes contact with said inner portion during the closing of said switch and wherein said switching member disengages said inner portion after said sleeve disengagessaid outer portion during the opening of said switch.

5. A high voltage circuit breaker comprising stationary contact means mounted on an insulation support, including a pair of contacts, each having inner and outer portions and an insulating member separating said inner and outer portion, insulating hood means movably mounted relative to .said stationary contact means, a pair of conducting sleeves mounted in said hood means in a position to engage respective ones of said outer portions, a switching member slidably mounted relative to said sleeves in a position to engage the inner portions of said stationary contact means, and means interconnecting said switching member and said conducting sleeves whereby said conducting sleeves make contact with said outer portions before said switching member makes contact with said inner portion during the closing of said switch and wherein said switching member engages said inner portions after said sleeves disengage said outer portions during the opening of said switch.

6. A high voltage circuit breaker according toclaim 5, wherein said switching member is a U-shaped member including a pair of arms, one arm of said U-shaped member being slidably mounted axially of each of said sleeves and wherein said means for retaining said switching member in a predetermined position includes plate means slidably mounted relative to said sleeves, first spring means between each of said sleeves and said plate means and second spring means compressed between said plate means and said contact member, whereby upon movement of the said insulating hood means away from said stationary. contact means, said switching member disengages said inner contact portion after said conducting sleeves disengage said outer c-ontact portions.

7. A high voltage circuit breaker according to claim 6, wherein said plate means includes a plate extending into a slot in each of said sleeves, which plate encircles the arms of said U-shaped member and acts to move said U-shaped member when said insulating hood is moved away from said stationary contact means.

8. A high voltage circuit breaker according to claim 7, further comprising magnetic means connected to said insulating support, positioned to exert a holding force on said plate means when said switch is closed, which holding force is overcome by said first spring means during the opening of said switch delaying device to prevent movement of said contact member until after said sleeves have disengaged said outer portions during the opening of said switch.

9. A high voltage circuit breaker according to claim 6, wherein said first spring means includes helical springs compressed between each of said sleeves and said plate member, and wherein said second spring means includes a helical spring compressed between said plate member and each of said contact members.

10. A high voltage circuit breaker according to claim 7, wherein said first spring means comprises a pair of helical springs, one mounted in each of said sleeves and compressed between said sleeve and said plate member, and wherein said second spring means includes a pair of helical springs, each encircling said switching member and compressed bet-ween said switching member and said plate member.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES lA TENT. OFFICE CERTIFICATE OF CORRECTION Patent N0a 3 ,Ol7,480 January 16 1962 Antonius Canisius Klaassen It is hereby certified that error appears in the above numbered pat- Y ent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 43, for "in" read out Signed and sealed this 13th day of November- 1962.

(SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Attesting Officer Commissioner of Patents ENT OFFICE CTION January 16 1962 Antonius Cani Patent No sius Klaassen are in the above numbered pat- It is hereby certified that error appe nd that the said Letters Patent should read as ent requiring correction a corrected below.

"in read out Column 1 line 43, for Signed and sealed this 13th day of November 1962.

(SEAL) Attest: ERNEST w. SWIDER DAVID LADD Conmlissioner of Patents Attesting Officer 

